Characterization of the Specificity of Monoclonal Antibodies against Mycobacterium tuberculosis by Crossed Immunoelectrophoresis

Abstract

The specificity of monoclonal antibodies against M. tuberculosis was determined by crossed immunoelectrophoresis. Radiolabeled, non-precipitating monoclonal antibody was incorporated in the top gel together with unlabeled polyvalent, precipitating anti-BCG antibody. Inclusion of labeled antibody in individual precipitate lines was demonstrated by autoradiography. Each monoclonal antibody was localized in a single precipitate line: antibody TB73 reacted with BCG antigen 56; TB71 and TB72 reacted with BCG antigen 78; and TB78 reacted with BCG antigen 78; and TB78 reacted with BCG antigen 82. The technique permits precise determination of the specificity of monoclonal antibodies at the level of reactivity with native immunogenic components of complex microorganisms without prior antigen purification.